mineral
Polished/tumbled brown jasper or brecciated jasper
Microcrystalline quartz (SiO₂), commonly including hematite, iron oxides, and assorted silicified fragments
AI-generated identification · may be incorrectTypically Mohs hardness 6.5–7, opaque to slightly translucent, brown-red with cream or gray patches, and a waxy to vitreous luster when wet or polished. It has cryptocrystalline quartz structure, no visible cleavage, and specific gravity around 2.5–2.7.
Identified More mineral →
Explore Polished/tumbled brown jasper or brecciated jasper in the encyclopedia →Identify your own rocks.
Get a report just like this from any photo, free.
Physical properties
Typically Mohs hardness 6.5–7, opaque to slightly translucent, brown-red with cream or gray patches, and a waxy to vitreous luster when wet or polished. It has cryptocrystalline quartz structure, no visible cleavage, and specific gravity around 2.5–2.7.
Formation & geological history
Jasper forms when silica-rich fluids replace or cement volcanic, sedimentary, or hydrothermal material; iron oxides create the reddish-brown coloration. Formation ages vary widely, from Precambrian to relatively young hydrothermal deposits.
Uses & applications
Used for beads, cabochons, carvings, tumblestones, paperweights, and ornamental objects; lesser-quality material has limited industrial value.
Geological facts
The image shows a water-wet, rounded specimen, so surface gloss exaggerates its polish and colors. Exact identification would require a dry examination and ideally a hardness or microscopic test.
Field identification & locations
Look for opaque, fine-grained texture, absence of cleavage, and resistance to scratching by steel; quartz-rich jasper should not be scratched by a knife. Common sources include India, Madagascar, Brazil, Australia, Mexico, and the western United States.
